Bevacizumab is a monoclonal antibody that targets VEGF, which allows it to inhibit angiogenesis (growth of blood vessels). A previous study demonstrated that combining bevacizumab with paclitaxel resulted in improved response rate and progression-free survival in metastatic breast cancer. This study was conducted in Europe, where docetaxel is used more frequently than paclitaxel, and looked to combine bevacizumab with docetaxel.

736 participants with metastatic breast cancer were randomized to receive docetaxel + placebo (P), docetaxel + low dose bevacizumab (LD) or docetaxel + high dose bevacizumab (HD). Statistically significant advantages in progression-free survival (PFS) were seen in both bevacizumab arms. Median* PFS in the P arm was 8 months, 8.7 months for the LD arm, and 8.8 months for the HD arm. The percentage of patients who achieved at least a partial response were 44% (P), 55% (LD) and 63% (HD). Survival was not reported, as the median follow up is only 10 months, and more mature data is needed to evaluate survival. Limited toxicity was seen, according to the authors.

The PFS benefit was small in this trial, compared with the trial of paclitaxel and bevacizumab, which saw a greater benefit (5.9 versus 11.8 months). In that trial, paclitaxel was given weekly, which may account for the improvement in PFS. Ongoing studies (RIBBON trial) will further investigate adding antiangiogenesis agents to the treatment options in metastatic breast cancer.

* The median is the "middle of the pack", where half of the patients have had more years since treatment and half have less. For instance, if the patients were 2, 4, 6, 10.8, 12, 12 and 14 years since treatment, 10.8 is the mid point, or the median. It is different from the mean, which would be the average time since treatment.